1 files changed, 34 insertions, 36 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 8095c607a494..f65e69d94527 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -173,15 +173,11 @@ retry:
  * 2 for pages with a mapping
  * 3 for pages with a mapping and PagePrivate set.
  */
-static int migrate_page_move_mapping(struct page *newpage,
-                                struct page *page)
+static int migrate_page_move_mapping(struct address_space *mapping,
+                struct page *newpage, struct page *page)
 {
-        struct address_space *mapping = page_mapping(page);
         struct page **radix_pointer;
 
-        if (!mapping)
-                return -EAGAIN;
-
         write_lock_irq(&mapping->tree_lock);
 
         radix_pointer = (struct page **)radix_tree_lookup_slot(
@@ -197,15 +193,8 @@ static int migrate_page_move_mapping(struct page *newpage,
 
         /*
          * Now we know that no one else is looking at the page.
-         *
-         * Certain minimal information about a page must be available
-         * in order for other subsystems to properly handle the page if they
-         * find it through the radix tree update before we are finished
-         * copying the page.
          */
         get_page(newpage);
-        newpage->index = page->index;
-        newpage->mapping = page->mapping;
         if (PageSwapCache(page)) {
                 SetPageSwapCache(newpage);
                 set_page_private(newpage, page_private(page));
@@ -262,7 +251,8 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
  ***********************************************************/
 
 /* Always fail migration. Used for mappings that are not movable */
-int fail_migrate_page(struct page *newpage, struct page *page)
+int fail_migrate_page(struct address_space *mapping,
+                        struct page *newpage, struct page *page)
 {
         return -EIO;
 }
@@ -274,13 +264,14 @@ EXPORT_SYMBOL(fail_migrate_page);
  *
  * Pages are locked upon entry and exit.
  */
-int migrate_page(struct page *newpage, struct page *page)
+int migrate_page(struct address_space *mapping,
+                struct page *newpage, struct page *page)
 {
         int rc;
 
         BUG_ON(PageWriteback(page));    /* Writeback must be complete */
 
-        rc = migrate_page_move_mapping(newpage, page);
+        rc = migrate_page_move_mapping(mapping, newpage, page);
 
         if (rc)
                 return rc;
@@ -305,21 +296,18 @@ EXPORT_SYMBOL(migrate_page);
  * if the underlying filesystem guarantees that no other references to "page"
  * exist.
  */
-int buffer_migrate_page(struct page *newpage, struct page *page)
+int buffer_migrate_page(struct address_space *mapping,
+                struct page *newpage, struct page *page)
 {
-        struct address_space *mapping = page->mapping;
         struct buffer_head *bh, *head;
         int rc;
 
-        if (!mapping)
-                return -EAGAIN;
-
         if (!page_has_buffers(page))
-                return migrate_page(newpage, page);
+                return migrate_page(mapping, newpage, page);
 
         head = page_buffers(page);
 
-        rc = migrate_page_move_mapping(newpage, page);
+        rc = migrate_page_move_mapping(mapping, newpage, page);
 
         if (rc)
                 return rc;
@@ -448,9 +436,6 @@ redo:
                         goto next;
                 }
 
-                newpage = lru_to_page(to);
-                lock_page(newpage);
-
                 /*
                  * Establish swap ptes for anonymous pages or destroy pte
                  * maps for files.
@@ -473,11 +458,18 @@ redo:
                 rc = -EPERM;
                 if (try_to_unmap(page, 1) == SWAP_FAIL)
                         /* A vma has VM_LOCKED set -> permanent failure */
-                        goto unlock_both;
+                        goto unlock_page;
 
                 rc = -EAGAIN;
                 if (page_mapped(page))
-                        goto unlock_both;
+                        goto unlock_page;
+
+                newpage = lru_to_page(to);
+                lock_page(newpage);
+                /* Prepare mapping for the new page.*/
+                newpage->index = page->index;
+                newpage->mapping = page->mapping;
+
                 /*
                  * Pages are properly locked and writeback is complete.
                  * Try to migrate the page.
@@ -494,7 +486,8 @@ redo:
                          * own migration function. This is the most common
                          * path for page migration.
                          */
-                        rc = mapping->a_ops->migratepage(newpage, page);
+                        rc = mapping->a_ops->migratepage(mapping,
+                                                        newpage, page);
                         goto unlock_both;
                 }
 
@@ -524,7 +517,7 @@ redo:
                  */
                 if (!page_has_buffers(page) ||
                     try_to_release_page(page, GFP_KERNEL)) {
-                        rc = migrate_page(newpage, page);
+                        rc = migrate_page(mapping, newpage, page);
                         goto unlock_both;
                 }
 
@@ -553,12 +546,17 @@ unlock_page:
                 unlock_page(page);
 
 next:
-                if (rc == -EAGAIN) {
-                        retry++;
-                } else if (rc) {
-                        /* Permanent failure */
-                        list_move(&page->lru, failed);
-                        nr_failed++;
+                if (rc) {
+                        if (newpage)
+                                newpage->mapping = NULL;
+
+                        if (rc == -EAGAIN)
+                                retry++;
+                        else {
+                                /* Permanent failure */
+                                list_move(&page->lru, failed);
+                                nr_failed++;
+                        }
                 } else {
                         if (newpage) {
                                 /* Successful migration. Return page to LRU */